Submarines/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim is holding a letter and seated by a pool. Moby is standing on a diving board. TIM: Hey Moby, check this one out! Moby dives into the pool and touches the bottom of it with his feet. Tim reads from the typed letter. TIM: Dear Tim and Moby, how does a submarine sink and move? From, Arthur Jr. Good question! First, a little background. A submarine is a vehicle designed to function deep below the ocean's surface. An image shows a submarine. TIM: Although ideas for a submersible, or underwater vessel, had come up before, people really began working on submarines in the 1600s. Many inventors from around the world contributed to their development. An image shows three inventors standing in front of flags from the countries they're from: United States, Spain and France. TIM: From the very beginning, submarines have been used primarily for warfare. Something called the Turtle is generally considered the first successful military submarine. It was used in the American Revolutionary War against the British. An image shows the Turtle with a man inside it. It looks like a large metal egg with a propeller. The man inside steers with an array of pedals and levers. TIM: These days, there are still plenty of military subs, but you can also find them being used for commercial and scientific exploration of the oceans. An animation shows a nonmilitary submarine. TIM: Conventional submarines run using a combination of diesel combustion engines and electric batteries. The engines, which need air to operate, charge the batteries while the sub is on or near the surface. An image shows a sub partly submerged in water, next to a diesel can. TIM: When the sub goes deep, the batteries take over. The image shows the sub in deeper water and a battery. TIM: Some subs run on nuclear power, using an internal reactor. An image shows the door to a reactor room on a sub. It has a hazard sign on it, which reads: Please do not enter. No, really. Don't come in here. TIM: Nuclear submarines can travel up to 640,000 kilometers without refueling! An animation shows a submarine traveling in deep water. TIM: Subs come in different shapes and sizes, depending on what they're being used for. An animation shows different types and shapes of subs. TIM: Most submarines move through the water by means of propellers and steer with fins called hydroplanes. Side by side animations show propellers and hydroplanes. MOBY: Beep. Moby blows bubbles from underwater in the pool. TIM: Oh, there you are. MOBY: Beep. TIM: Moby wants me to get to Arthur Jr's question already. Can I help it if I'm a fountain of knowledge about submarines? MOBY: Beep. TIM: Alright, fine. Inside every sub is a system of hollow spaces called ballast tanks that can be filled with either pressurized air or water. An animation shows the ballast tanks inside the bottom of the sub. TIM: When the submarine needs to dive, water is pumped into the ballast tanks, giving the sub a higher density than seawater. The hydroplanes steer the sub downward, and it is propelled forward into a dive. The animation shows the ballast tanks filled with seawater, then diving into deeper water. TIM: Filling the tanks with air causes the submarine's overall density to be lower than the surrounding water. The sub floats to the surface. The animation shows the ballast tanks filled with air and the sub floating to the surface. TIM: And, if the sub wants to hover at a certain depth, it can fill the tanks halfway, giving the sub the same density as seawater. The animation shows the ballast tanks half-filled with water and the sub hovering just below the surface. Back at the pool, a periscope pops out of the water behind Tim and looks around. TIM: Moby thinks he's pretty slick. A periscope is a tube that can be raised from the submarine to the surface, so submariners can see what's going on topside. A periscope can work via a system of mirrors, or using a video camera. The periscope's view is shown. It moves around until it focuses on the back of Tim's head. Moby is shown in the water. The periscope was raised from inside Moby's head. He lowers it back into his head and laughs. He shoots out of the pool high into the air. MOBY: Beep. Moby falls back down in a diving position and crashes into the ground next to where Tim is sitting. TIM: I didn't know you had ballast tanks. Moby sprays Tim in the face with water. TIM: Aaah! Category:BrainPOP Transcripts